And edward blakeney



(.No' Model.)

J. M. MOFFATT & E. BLAKENEY.

vQUADRU PLEX TELEGRAPHY.

No. 351,933. Patented Nov. 2, 1886.

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AEFENT OFFICE.

LYN, N. Y.

V .QU-ADIRUPUEX TaELEGRAiPHY.

aSBECIFIGATIGNTorming part of ,Letters Patent No. 351, 933, dated November 2, 1886. v Application filed July 3, 1886. Serial No. 207,047. (No model.)

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Be it known that we, JOHN M. MoFFA'rrand EDWARD BLAKENEY, citizens of thejUnitcd States, and residents, respectively, of New York,-in the=county and State of New York.

and'of Brooklymdn the county-of Kings and State of New 'Yor-k,;have-invented certainnew and usefnlvlmprovements in Quadruple); Te-

legraphy, of whichthe following is a specification.

*Theinvention relates to the class-of-appa- .ratusemployedfor transmitting twomessages simultaneously in the same direction-over-a single telegraph "mainline-and it naturally involves" the d'uplexing-of such system also.

The object of thefi'n-vention is to provide convenient-and effecti-v-emeans for preventing. the. false signalswhich are usually manifest in the neutral relay, and --caused by reversal of the polarity of the current-upon the line-at the :distantstation.

In the accompanying drawings, which illustrate :the invention,- Figure 1 is a diagram :showingthe general organization of circuits and apparatus embodying the prin cipleof our invent-ion, and Fig-.Qillustratesa slight modification. Fig. 3 is a-modifiedformof inductor. Referring-to Fig. 1, Lrepresentsa telegraphmain, and K and K, respectively, representa "key for increasing thestrengthot' currents'and a pole-changingkey fortransmitting currents from1aiba ttery, O. One pole of this battery is connectedwith the lever of the key K and when-the. keys areinthe'position shown its connections are continued through the'key K to the earth at G. Theothenpole isconnect'ed with the reversing key K in a mannerswell understood. The battery is divided, as shown, by a conductor leading from an intermediate point to the key K which, when operated, places alternately the whole and a portion of the battery to line through the key K and a conductor leading to a point, 2. From this point 2 two conductors, 3 and 4, lead, respectively, to the main line L and to an artificial line, L. A differentially-wound receiving-instrument, R, has its respective coilsincluded in the main line L and in the artificial line L. This instrument is provided with a'polarized andb. circuitand thecoil b in theartificial line. The supplemental coil b is included in an independent circuit, and is employed for maintainarmature, and, constructed in any convenient well-known manner as a polarized receiving instrument or relay.

The second or neutral receiving-instrument,

BLAKENEY, or BROOK- R", isconstructed with three sets of coils,'b,'b,

The coil b is included in the main-line ing. the magnetism of the core of this receiving-instrument during the reversals in the mainline current. This is accomplished by sending a momentary impulse through the coils b" at the moment of re versal. Suchan impulse is derived from an inductorium or inductioncoil, I. This :coil is constructed in any convenient manner. -F0r instance, it may =be=a closed magnetic ring or rectangular framei,

having coils z" i i i wound upon it. The

coils i are included, respectively, in the mainline L and artificial line L. The coils i and z" are connected through the supplemental coil b ofthe receiving-instrnment R".

Variations in the strength of the current traversing the line will, it is evident, cause variations in the magnetism of the core, and thus induce currents in the coils L and i The efl'e'ct of this induced current is to prevent the armatureof the neutral relay from falling against the back-stop and remaining there long enough to give a false signal at the instantof the reversal of the current,caused by the operation of the pole-changing key, and this is done in the following manner: When a-current inonedirection is passing through 'theneutral relay it producesmagnetism-in the core of a certain-polarity. When this current Now, the effect of the in netism due to the reversal of the current. Thus both operations are facilitated by the operation of the induced current and the time so shortened that the armature cannot reach the back contact, but is held practically without interruption to its front contact.

For the purpose of assisting the operation a condenser, C, may be connected across the terminals of the inductioncoil, as shown, and the discharge from this condenser upon varia tions or reversals in the magnetism of the induction-coil will serve to sendimpulses of the proper character through the coil 1) momentarily. There are several difierent ways in which the same general result may be accomplished, but one variation only will be described, since this will serve to fully illustrate the principle of the invention.

In Fig. 2 an arrangement as applied to a \Vhea-tstone bridge is illustrated. One arm, w, of this bridge leads from the point 2to the main line L, and the other arm, to, to the artificial line L. Bridge-conductor 10 includes the polarized relay R and the neutral relay R and also the primary of the induction-coil I. The secondary of this coil, is connected through the supplemental coil b of the neutral relay in the same manner and with the same effect as was described with reference to Fig. 1.

Fig. 3 is a form of inductor which gives excellent results in practice. The coils intended for both the main and artificial lines have two each about seventy-five ohms resistance. The secondary coils have about seventy-five ohms resistance, respectively. When the coils are connected in series,a satisfactory induced current is obtained, and when connected up for practical operation, as already described with reference to Fig. 1, produces the effect of practically destroying all trace of false signals.

Instead of. the separate inductor, as shown, a supplemental coil may be added to the polar relay, and this is connected with the supplemental coil of the neutral relay in the same manner as the secondary wire of the inductor. In this case the polar relay becomes the inductor and produces the same effect upon the neutral as the separate inductor already described. In this case a condenser may be placed between tlie supplemental coils in the same manner and with the same effect as described with reference to the separate induction and neutral relay. Considering the inductor in Fig. 2 as being provided with a po larized armature and the instrument R dispensed with, this organization would operate as described.

We claim as our invention 1. The combination, with a polarized and neutral relay of a telegraph system and means for causing said instruments to respond to illcoming and be silent to outgoing currents, of a supplemental coil applied to the neutral relay, an induction-coil havingits'primary wire connected in the main circuit and its secondary wire through said supplemental coil of the neutral relay, and a condenser having its respective plates connected to the terminals of the secondary coil.

2. The combination, with a polarized and a neutral relay, both of which are differentially wound, of a main and artificial line, respectively, including the opposing coils of said relays, an induction-coil having its primary wire included in the main and artificial lines, and a circuit for the secondary coil in which said sup plemental coil is included, the connections being such as to cause the induced currents from the secondary coil to assist in the rapid discharge and recharge of the magnetism in the coils of the neutral relay at the instant of re versal.

3. The combination, with a main and artificial line, of a polarized and neutral relay, means for transmitting currents of alternating polarity and different Strength upon Said lines, and supplemental coils in said polarized and neutral relays, which supplemental coils are connected together.

4. The combination, with a main and artificial line, of a polarized and neutral relay, means for transmitting currents of alternating polarity and of different strength upon said lines, and supplemental coils in said polarized and neutral relays, which supplemental coils 9 5 are connected together, and a condenser hav- ,ing its plates connected to the terminals of said supplemental coils. p

In testimony whereof we have hereunto subscribed our names this 1st day of July, A. D. I0) 1886.

JOHN M. lVIOFFA'lT. EDWARD BLAKENEY. Witnesses:

JENNIE P. ASHLEY, DANL. W. EDGECOMB. 

